This invention relates to automatic packaging machines and more particularly to method of and means for folding, forming and closing self-latching boxes with a flip top.
Reference is made to the following U.S. Patents, assigned to the assignee of this invention, which provide background information on automatic packaging machines: U.S. Pat. Nos. 4,578,929; 4,548,593; 4,716,714; 4,829.751; 4,856,566; 4,982,556; 5,010,929; 5,072,573; and U.S. Pat. No. 5,144,790. Co-pending U.S. patent applications Ser. No. 08/848,127 filed Apr. 27, 1997 and Ser. No. 08/856,443 filed May 14, 1997 are examples of a type of packaging machines which may be used to load small items, such as candy-coated chewing gum into a different kind of box.
Conventional automatic packing machines have a conveyor, usually an endless link chain conveyor, which travels through or past a number of work stations extending between a magazine containing package blanks and a product discharge end. Usually, the package blanks are a stack of die cut cardboard blanks which are picked up one-at-a-time by vacuum cups and then put into box forming mandrels carried by the conveyor. Tabs and flaps on the bottom of the blank are folded by plows and sealed in order to close the box. Then a pre-determined amount of product is placed in the box. Next, tabs and flaps forming a top of the box are folded and sealed. Then the box is discharged on to any suitable conveyor, into a shipping carton, or to another device for receiving the completed product containing packaging.
Conventionally, a plow is a strip of metal, or the like, extending along a length of the conveyor and in a location where the tabs and flaps are to be folded. First, tabs and flaps forming the bottom of the box encounter the plows and they are folded as the conveyor carries the box past the plow. Then, a pre-determined amount of product is placed in the box. Next, tabs and flaps forming a top of the box are folded and sealed in a similar manner. Depending upon product packaging needs, the box may or may not be wrapped in a transparent film which is sealed. Finally, the box is discharged on to any suitable conveyor, into a shipping box or to another suitable device for receiving the product containing packaging.
Often, the product presents special considerations which require the packaging machine to perform unique functions as the box is formed and filled. These functions may be performed by special parts which are attached to or positioned near the conveyor. Many examples of such special parts are shown and described in the above-cited patents.